#main {
  width: 408px;
  height: 408px;
  background: white;
  border: 2px solid gray;
  margin: 0 auto;
  overflow: hidden;
  position: relative;
}

h2 {
  text-align: center;
}

#con {
  width: 100%;
  height: 400px;
  position: relative;
  top: -408px; /*隐藏所有格子*/
  border-collapse: collapse;
}
/* 行 */
.row {
  height: 100px;
  width: 100%;
}
/* 一个块 */
.cell {
  height: 100px;
  width: 100px;
  float: left;
  border: rgb(54, 74, 129) 1px solid;
}

.black {
  background: black;
}

.btn {
  width: 100%;
  text-align: center;
}

.start {
  margin: 20px auto;
  width: 150px;
  height: 50px;
  border-radius: 10px;
  background: yellowgreen;
  line-height: 50px;
  color: #fff;
}

.abc{
  width: 350px;
  position: absolute;
  top: 200px;
  left: 1010px;
}